Earth Is 2,000 Light-Years Closer To The Center Of The Milky Way Than We Thought

The masers studied in this work and their position and proper motion. NAOJ

There are a lot of barriers in studying our galaxy, the Milky Way, and the Solar System's position in it. Mostly this is because we are in it, so can’t get a good view of it all. This means estimations are constantly being refined and improved.

Researchers at the National Astronomical Observatory of Japan have collected new data that has allowed some more precise measurements and revealed some new calculations, such as the Earth is 2,000 light-years closer to the galactic center and the Solar System is orbiting the Milky Way 7 kilometers per second (15,660 mph) faster than previously thought.

As reported in the Publications of the Astronomical Society of Japan, researchers estimated that the Sun is about 25,800 light-years from Sagittarius A*, the supermassive black hole at the core of the Milky Way. They also calculated the Earth goes around the Milky Way at 227 kilometers (141 miles) per second – a whopping 817,200 kilometers (508,000 miles) per hour – and not the official 220 kilometers per second previously thought.

The new estimates come from the VERA project. VERA stands for VLBI Exploration of Radio Astrometry and VLBI stands for Very Long Baseline Interferometry. And yes, astronomers really are suckers for acronyms. Interferometry is a technique commonly used in radio astronomy that allows the combination of different radio dishes to effectively become one giant telescope.

The masers studied in this work and their position and proper motion. NAOJ

The project uses radio observatories located across the Japanese Archipelago, which allowed them to achieve the resolution of a single radio dish 2,300 kilometers (1,430 miles) in diameter. That’s sharp enough to see a US penny on the surface of the Moon.

With this system, the researchers measured the precise distance, position, and proper motion of 99 galactic maser sources. A maser is a microwave-emitting source akin to a laser, that can be found in the atmosphere of stars, in star-forming regions, and several other astrophysical sources. Twenty-one of these masers were discovered in this study. By using these objects, the team was able to estimate more precisely where the Solar System is.

“Because Earth is located inside the Milky Way Galaxy, we can't step back and see what the Galaxy looks like from the outside. Astrometry, [the] accurate measurement of the positions and motions of objects, is a vital tool to understand the overall structure of the Galaxy and our place in it,” the team writes in a press release.

Observations of these objects using VERA started two decades ago so this first data release is a culmination of long and difficult work. It's also an exciting beginning. VERA will become part of EAVN, the East Asian VLBI Network (I wasn’t wrong about the acronyms) that will make it even more precise in measuring these and many more objects' properties.


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